Bob Potvin's weather for West Brookfield and central Massachusetts

Potvin Gold Exchange
132 East Main Street
P.O. Box 7
West Brookfield, MA 01585
Telephone: (508) 867-3360
Email: serv@GoldRedeemer.com
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Bob Potvin's Weather

West Brookfield weather
West Brookfield and the surrounding communities have weather that is most always slightly different from the weather forecasts heard on the radio or seen on television. This is because of the terrain surrounding the West Brookfield area.

After the famous Worcester tornado in 1953, Bob Potvin and his friends started to take an increased interest in the local weather. Adding to the intrigue was WBZ-TV weatherman, Don Kent. Don was one of the first weather forecasters to understand that local weather is affected by terrain, so simply looking at a national weather map and guessing about the arrival of a storm was not quite enough. The forecast of the arrival time of a storm could be off by as much as a day.

Three major weather types
Although there are many weather compositions, there are three most important to West Brookfield residents. They are nor’easter snowstorms, hurricanes, and air mass thunderstorms.

Nor’easters
Every winter season brings at least one nor’easter, which is the winter equivalent of a hurricane. These are generally born in tropical waters, move up the coast, and sit offshore in the Atlantic, bringing huge volumes of snow to New England.

Hurricanes
Hurricanes are also born in the warm moist tropical waters and then move up the coast. Many dissipate before they reach New England, but the great New England flood of 1927 is an example of what can happen even when a hurricane is dissipating. It rained for 10 days, destroyed or damaged practically everything, and killed 200 people. The flood of August 18-23, 1955, was caused by hurricanes Connie and Diane, which occurred days apart, resulting in loss of life and extensive property damage. Much of Massachusetts river-town industry was destroyed, causing the elimination of thousands of local jobs. As recently as May 22, 2006, there were record rainfall totals between 10 and 15 inches in some areas of northeastern Massachusetts, and 3 to 8 inches fell in most other areas.

Thunderstorms
Air mass thunderstorms are locally generated thunderstorms, not generally associated with major weather systems. The 1953 tornado was associated with an air mass thunderstorm. New England has a history of many small tornados. Most go unnoticed because they affect small remote areas. For instance, in the summer of 2008 a tornado in New Braintree uprooted a few trees and damaged several outbuildings. Although the Worcester Telegram newspaper reported it, no reports were present on any major city television stations.

Local effects of the terrain
Let us follow the typical life of an air mass thunderstorm as it approaches West Brookfield. This will show how local terrain changes the weather. The storm typically brews as warm moist air moves from south to north, up the Susquehanna River valley in Pennsylvania. Once it moves into upstate New York, it interacts with colder air moving off the great lakes. Cumulonimbus (thunderstorm) clouds form and the storm increases in intensity.

Moved eastward by the prevailing westerly winds, the storm forms a squall line, generally northeast to southwest. It may be 80 or more miles in length and perhaps 10 miles across. Such a line generally moves towards New England at 20 to 30 miles per hour. If one looked at satellite photographs of the developing storm, and predicted its arrival based upon its speed across the ground, the prediction will be wrong. The Pocono Mountains affect the storm and slow it down as it approaches the Hudson River valley. This makes the storm linger longer than expected in towns like Binghamton, New York. As the storm approaches the Hudson River, it moves down-slope, which causes its progress to speed up. It may now be traveling 40 to 50 miles per hour. When the thunderstorm is reported at Albany, it is fast moving and generally of short duration.

The squall line then “slams” into the Berkshire Mountains in western Massachusetts. This forces the air mass upward, slowing its progress. The altitude increase causes a change in temperature difference, which may cause the storm to mature and dissipate over the mountains. Persons living in Western Massachusetts often see an ominous black sky over the Berkshires, foreboding the coming of a violent storm. Then the sky clears as it dissipates --sometimes. If the Berkshires did not cause the storm to dissipate, it starts downhill towards the Connecticut River valley, called Pioneer Valley, and intensifies as it picks up moisture from the fair- weather flow of warm moist air from Long Island Sound, traveling northward up the river.

By the time the storm reaches the Quabbin Reservoir area, it may have formed a line from Hartford, Connecticut to Keene, New Hampshire. The Quabbin Reservoir is large and is generally cooler than the summertime air. This causes the squall line to slow down and lose some intensity as it moves over the reservoir. The portions of the storm north and south of the reservoir are not affected so they continue eastward at predictable speeds. However, West Brookfield is in the leeward flow off the reservoir. North Brookfield residents may see the storm that was brewing in the west, moving both north and south of them as the Quabbin forces a break in the squall line.

As the storm continues to move east, the portion broken by the reservoir regroups and the altitude increase of Massachusetts’s mid-state bulge, topped by Mount Wachusett, begins to affect it. This slow increase in altitude causes a temperature change that may force the storm to dissipate in the Nashua River watershed, helping to replenish the Wachusett Reservoir in Clinton. This keeps Boston’s residents happy because it is their water supply.

If the storm is able to survive interference from the mid-state bulge, it starts downhill again towards the Boston area and generally follows the path of the Merrimack River out to sea. So ends the life of an air mass thunderstorm born in Northern Pennsylvania.

The local terrain affects all of West Brookfield’s weather so the weather forecasts reported by the talking heads at the television stations may not be very accurate. However, longtime New England residents learn to interpret what they see on television and hear on the radio. They understand that storms will not arrive at the times predicted and they generally plan accordingly.
---- Richard B. Johnson ----

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